Battey keeps flatting

[CeriUK]

I have a UX 250e h 43 k miles driven

and during a recent cold snap my 12v Battery did not have enough charge to start the car. 
 

I jump started it easily and done some motorway journeys 

However if I don’t use or start the car for 4 days or more it flats again 

do I have a dead Battery or is it a symptom of something else please?

the hybrid Battery is fine and had a perfect health check during my last Lexus service 

 

 

 

[steve2006]

Hi Ceri and welcome to the LOC. 😀

At 4 years old and with temperatures now falling the prime suspect, I agree, would be the 12Volt Battery.

Personally I would take it to the dealer for a check and not one of the “Free Battery Check” places where one of their “load tests” could create additional issues with the car’s computers if the voltage falls excessively.

Basically if Lexus mess it up the car is already there and they will have to sort it.

Although I have a petrol V8 the fact it spends more time in the garage not being used than driven plus mainly local trips when it is usually kills my Battery in 3-4 years.

[Lexusjim]

Ceri

Welcome 

 

I agree with Steve. Most  likely a failing 12v Battery. 

Once the car returns from the dealer (hopefully with a nice new Battery,  I recommend  fitting a Battery monitor such as: 

https://www.ancel.com/products/ancel-bm200

that way you can easily keep an eye on it to ensure it stays in top condition.  You are probably aware that it is a big no-no to have the car in accessory mode....it can flatten the Battery in 20 minutes...always ensure it is in ready mode if you are in it. 

Additionally,  if the vehicle is not being used for days at a time, you might consider a trickle charger, such as https://www.amazon.co.uk/gp/product/B07JLX9J15/

(Other makes are available) 

A jump starter such as

https://www.amazon.co.uk/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B015TKUPIC?

is also a useful purchase. Lots of arguments on the forum along the lines of 'you shouldn't have to buy these items for a car that costs  £xxxxx' however I prefer to be 'looking at them rather than looking for them'

It's a lovely car....don't let this put you off

 

[Pauly C]

Notwithstanding the above, I am (very) reliably informed a driver does not need to go out for a thrash up and down the motorway to charge up a half dead battery…..having the engine idling (if you can get it started) will charge up a Battery just as quick, and will use less fuel😉

[Notamech]

27 minutes ago, Pauly C said:

Notwithstanding the above, I am (very) reliably informed a driver does not need to go out for a thrash up and down the motorway to charge up a half dead battery…..having the engine idling (if you can get it started) will charge up a battery just as quick, and will use less fuel😉

Yes thats correct. Thats because once the computers have booted it is the inverter that charges the Battery. It does this using power from the traction Battery. So whether the engine is running at 1000 rpm or 5000 rpm is immaterial as all it needs to do is charge the traction Battery which in turn provides the inverter power to charge the 12v Battery. You need at least 30 mins of charge per week i think.

[RONNIE W HODGEKINSON]

1 hour ago, Pauly C said:

Notwithstanding the above, I am (very) reliably informed a driver does not need to go out for a thrash up and down the motorway to charge up a half dead battery…..having the engine idling (if you can get it started) will charge up a battery just as quick, and will use less fuel😉

Great Advice

[CeriUK]

1 hour ago, Pauly C said:

Notwithstanding the above, I am (very) reliably informed a driver does not need to go out for a thrash up and down the motorway to charge up a half dead battery…..having the engine idling (if you can get it started) will charge up a battery just as quick, and will use less fuel😉

Thanks Pauly,

The motorway journey’s were required anyway! Taking daughter to university and normal trips anyway. 

Great expert advice and thanks. 

Ceri

[CeriUK]

3 hours ago, steve2006 said:

Hi Ceri and welcome to the LOC. 😀

At 4 years old and with temperatures now falling the prime suspect, I agree, would be the 12Volt battery.

Personally I would take it to the dealer for a check and not one of the “Free Battery Check” places where one of their “load tests” could create additional issues with the car’s computers if the voltage falls excessively.

Basically if Lexus mess it up the car is already there and they will have to sort it.

Although I have a petrol V8 the fact it spends more time in the garage not being used than driven plus mainly local trips when it is usually kills my battery in 3-4 years.

Steve, 

thanks for your kind welcome and expert advice. Off to a Lexus dealer I go. 
 

Will feedback anything different or interesting. 

PS recently driven the RZ450e !!! Wow stunning, drives like a sports car despite the size! Also had a 500 mile drive of the RX450h+. That thing shifts! 
 

All the best 

 

Ceri

[CeriUK]

3 hours ago, Lexusjim said:

Ceri

Welcome 

 

I agree with Steve. Most  likely a failing 12v battery. 

Once the car returns from the dealer (hopefully with a nice new battery,  I recommend  fitting a battery monitor such as: 

https://www.ancel.com/products/ancel-bm200

that way you can easily keep an eye on it to ensure it stays in top condition.  You are probably aware that it is a big no-no to have the car in accessory mode....it can flatten the battery in 20 minutes...always ensure it is in ready mode if you are in it. 

Additionally,  if the vehicle is not being used for days at a time, you might consider a trickle charger, such as https://www.amazon.co.uk/gp/product/B07JLX9J15/

(Other makes are available) 

A jump starter such as

https://www.amazon.co.uk/NOCO-GB40-UltraSafe-Lithium-Starter/dp/B015TKUPIC?

is also a useful purchase. Lots of arguments on the forum along the lines of 'you shouldn't have to buy these items for a car that costs  £xxxxx' however I prefer to be 'looking at them rather than looking for them'

It's a lovely car....don't let this put you off

 

Jim,

Thank you. 

Having the car in ‘Accessory Mode’. 

Not sure if my car is in  Accessory Mode’, what ‘Accessory Mode’ is or how to put it into and take it out of  Accessory Mode in the first place. For all I know it might be in that mode. 
 

Put me right please ?

Thanks,

Ceri

[CeriUK]

1 hour ago, Notamech said:

Yes thats correct. Thats because once the computers have booted it is the inverter that charges the battery. It does this using power from the traction battery. So whether the engine is running at 1000 rpm or 5000 rpm is immaterial as all it needs to do is charge the traction battery which in turn provides the inverter power to charge the 12v battery. You need at least 30 mins of charge per week i think.

Currently my Battery seems to be flatting after 3 or 4 days of non use 🤔

[Lexusjim]

5 minutes ago, CeriUK said:

Jim,

Thank you. 

Having the car in ‘Accessory Mode’. 

Not sure if my car is in  Accessory Mode’, what ‘Accessory Mode’ is or how to put it into and take it out of  Accessory Mode in the first place. For all I know it might be in that mode. 
 

Put me right please ?

Thanks,

Ceri

Ceri

If you haven't already done so, download the car's manuals (a vehicle one and a separate one for navigation)  from

https://www.lexus.co.uk/owners/about-my-lexus/manuals?utm_source=LexusOwnersClubUK&utm_medium=ForumLinks

The paper one that comes with the car is just a quick start guide.

For example,  my paper manual is around 300 pages, while the online one is 500 plus another 250 for navigation

See around page 188 (it will vary depending on the car model) 

 

[stepppy]

*posted in error, question already answered- please delete*

[CeriUK]

Jim, 

Thank you for educating me, and sharing this important knowledge. 

Maybe I might not always of ‘turned’ the car off properly. 🤔

Good to know! Evidently older cars still do some things better, in this case switching off. 😂

However I love the HUD and the self driving mode which are both mind blowing.😊 

I’ll make sure to look after my new 12v Battery better. 

Crazy that Lexus don’t give new car owners proper manuals  

Happy days 

Ceri

 

 

 

 

[ColinBarber]

16 minutes ago, CeriUK said:

Maybe I might not always of ‘turned’ the car off properly. 🤔

You will get warning beeps if the car isn't turned off.

What is important is if you are just sitting in the car listening to the radio or programming a route in to the Sat Nav that you put the car into 'Ready' mode (foot on the brake and press the start button), even if that means the petrol engine will start and stop, and not just turn on accessory or ignition mode (pressing the button without your foot on the brake). If you aren't in ready mode then your Battery will go flat very quickly.

[CeriUK]

Oh been there done that 

ST out side A&E for 4 hours during lockdown not knowing if I was ever go to see my wife again.

Happily I did, but the car would not start!

3 hours of just listening to the the radio and keeping the phone fully charged and not getting cold was not smart.